Vacuum-operated devices generally require a minimum vacuum capacity, typically measured in volumetric flow of air per unit time, to ensure their proper operation. Consequently, vacuum systems supplying vacuum to such devices must likewise maintain sufficient vacuum capacity.
Typically vacuum within a vacuum system is produced by a vacuum pump, several types of vacuum pumps being well known to those of skill in the art. In a vacuum system, the vacuum pump must be designed and sized to ensure enough capacity. That is, the vacuum pump must be capable of providing more air flow than the system requires.
Vacuum systems typically include some means for regulating the vacuum level (i.e., holding the vacuum level between predetermined limits). This is typically accomplished either by using a regulator that admits air in a controlled manner or by varying the speed of the vacuum pump to produce the required instantaneous vacuum.
However, as vacuum pumps and other components in a vacuum system age, several problems may occur. These problems result in a decrease in vacuum capacity of the system. Problems such as mechanical wear and degradation of the pump, leaks in the system, or failure of the vacuum regulator are typical. The loss of vacuum capacity can occur gradually over time leading to slow erosion of the vacuum capacity margin of the system and subsequent degradation in the performance of vacuum-using devices attached to the system.
For example, one common usage of vacuum systems is in milking systems designed for milking dairy cows or other milk-producing animals. These milking systems consist of a vacuum pump, a regulator, and a collection of interconnecting pipes and milking machines that utilize the vacuum to milk cows. The process of milking the cows typically creates a widely varying vacuum demand. The vacuum pump must have the ability to respond to that changing demand in a timely manner.
If, however, the vacuum pump or other components of the vacuum system begin to degrade, then the performance of the milking system may be degraded. This degradation can occur over a period of time and may not be readily recognized by the operators until a catastrophic or near-catastrophic failure occurs. However, the result is generally poor milking performance of the milking system.